**4. Horticulture in the city**

In the last years and in different parts of the world, the way the city is inhabited has been transformed; the daily relationship between human beings and their natural environment within the city has changed [58]. During the twentieth century, urban agriculture reached a great development due to increasing urbanization, deterioration of life conditions in poor neighborhoods, wars, natural disasters, environmental degradation and lack of resources, which caused food shortage. Urban agriculture means food production within the cities, in most cases it is a small-scale activity scattered throughout the city [59]. The large number of community horticultural gardens located in charitable dining rooms and in vacant spaces (for example, under high-voltage lines or along roads and waterways), or in institutional spaces such as hospitals and businesses, family gardens in backyards and roofs and school gardens are just a few examples that show the growing presence of agriculture in the cities [60].

Food production within the city is mainly used for self-consumption, to improve the amount of available food, for its freshness, variety and nutritional value [61], for environmental education and the exchange of experiences, among other factors, as [62] points out. It is also associated with jobs generation and income for groups of individuals, and it promotes environmental sanitation through the recycling of organic waste [63]. As it is a multifunctional and multicomponent activity, urban agriculture can respond to a great diversity of urban issues that include from the fight against poverty and the strengthening of self-esteem, to the improvement of

the urban environment, participatory governance, management of the territory and food and nutritional security [60].
